Gaming machine pathways with unpredictable outcome

ABSTRACT

A gaming machine  10  has a display  14  and a game controller arranged to control images of symbols displayed on the display  14.  The game controller is arranged to play a game  16  in which at least one random event is caused to be displayed on the display  14.  If a predefined winning event occurs, the machine  10  awards a prize. When a game  16  played results in a feature being awarded, to arrive at a determination of a result of the feature, the controller selects a pathway having a number of steps, each step relating to a special outcome, with the number of steps taken along the pathway varying randomly from one feature to the next.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to Australian Provisional PatentApplication No. PS0502 filed Feb. 12, 2002, and is related to co-pendingU.S. patent application filed Feb. 12, 2003 entitled “Linked ProgressiveJackpot System” which claims priority to Australian Provisional PatentApplication No. PS0501 filed Feb. 12, 2002, and each of which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] This invention relates to a gaming machine. More particularly,the invention relates to a gaming machine and to an improvement to agame played on such a gaming machine.

BACKGROUND TO THE INVENTION

[0003] Players who regularly play gaming machines quickly tire ofparticular games and therefore it is necessary for manufacturers ofthese machines to develop innovative game features which add interest tothe games. In so doing, it is hoped to keep players amused and thereforewilling to continue playing the game as well as to attract new players.

[0004] Also, with the growth that has occurred in the gaming machinemarket, there is intense competition between manufacturers to supplyvarious existing and new venues. When selecting a supplier of gamingmachines, the operator of a venue will often pay close attention to thepopularity of various games with their patrons. Therefore, gamingmachine manufacturers are keen to devise games and/or game featureswhich are popular with the players as a mechanism for improving sales,retaining customers and attracting new customers.

SUMMARY OF THE INVENTION

[0005] According to the invention, there is provided a gaming machinehaving a display means and a game control means arranged to controlimages of symbols displayed on the display means, the game control meansbeing arranged to play a game in which at least one random event iscaused to be displayed on the display means and, if a predefined winningevent occurs, the machine awards a prize, wherein, when a game playedresults in a feature being awarded, to arrive at a determination of aresult for the feature, the control means selects a pathway having anumber of steps, each step relating to a special outcome, with thenumber of steps taken along the pathway varying randomly from onefeature to the next.

[0006] With the provision of these pathways, it is unnecessary to fix afeature outcome according to a pathway selected. Accordingly, althoughthe pathway is fixed once the feature occurs, the outcome of thatfeature is still not predictable because it remains unknown how far downthe pathway that feature will proceed.

[0007] The use of pathways is particularly advantageous where a randomfeature is awarded. Such random features occur, for example, when aseries of free games is awarded and the results of those free games arerandom. In such free games, special outcomes may occur where bonusprizes are awarded. These special outcomes may, for example, result fromthe occurrence of special symbols which, when acted on by a player ofthe game, are converted into the awarding of the special outcome being abonus credit prize, a bonus feature or a jackpot symbol. The jackpotsymbols may need to be accumulated so that, when a predetermined numberof the jackpot symbols have been accumulated, a jackpot prize isawarded.

[0008] In another embodiment of the invention, the feature event maycomprise a number of special outcome selections available to the player.The player may be prompted to make a selection from one of the specialoutcome selections where after, if the selection results in a positiveoutcome, the player may be offered another opportunity to select afurther special outcome, and so on until a number of steps have beentaken along the pathway or a negative outcome results. The specialoutcome selection may be based on steps taken along a pathway which maybe randomly selected from a set of pathways by the control means.

[0009] A set of pathways may be associated with each bet. Any number ofpathways may constitute each set. The pathways may be weighted so thatthose associated with larger bets provide an improved probability ofobtaining larger prizes than the pathways associated with smaller bets.

[0010] Further, each pathway may have a maximum number of steps that canbe taken down the pathway. For example, all the pathways in the set maybe fifty steps long and, if the fiftieth step is reached, the gamingmachine will not continue. Instead, the pathways may be of indefinitelengths where, if more than a predetermined number of steps down thepathway have been taken, thereafter each step along the pathway willprovide a fixed, low credit prize. It will be appreciated that, ingeneral, the chances of reaching such a large number of steps down apathway are extremely small.

[0011] In addition, there may be a minimum number of steps to be takendown a pathway in order to provide encouragement to the player. As anexample, at least three steps may be taken down a pathway during theplaying of the feature.

[0012] Still further, certain of the special outcomes may be collectedtowards a further event such as the awarding of a progressive jackpotprize. It will therefore be appreciated that, if the player succeeds ingetting far enough down the pathway, the player will have a good chanceof having collected enough of the special outcomes to win theprogressive prize.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention is now described by way of example with referenceto the accompanying diagrammatic drawings in which:

[0014]FIG. 1 shows a perspective view of a gaming machine, in accordancewith the invention;

[0015]FIG. 2 shows a block diagram of a control circuit of the gamingmachine;

[0016]FIG. 3 shows a flow chart of a first embodiment of a game playedon the gaming machine of FIG. 1;

[0017]FIG. 4 shows a table of a part of each of a number of pathwaysused in a second embodiment of a game played on the gaming machine; and

[0018]FIG. 5 shows a flow chart of the second embodiment of the game.

DETAILED DESCRIPTION OF THE DRAWINGS

[0019] In FIG. 1, reference numeral 10 generally designates a gamingmachine, including a game, in accordance with the invention. The machine10 includes a console 12 having a video display unit 14 on which a game16 is played, in use. The game 16 is, conveniently, a spinning reel gamewhich simulates the rotation of a number of spinning reels 18 but theinvention is not limited to spinning reel games. A midtrim 20 of themachine 10 houses a bank 22 of buttons for enabling a player to play thegame 16. The midtrim 20 also houses a credit input mechanism 24including a coin input chute 24.1 and a bill collector 24.2.

[0020] The machine 10 includes a top box 26 on which artwork 28 iscarried. The artwork 28 includes paytables, details of bonus awards,etc. and may further include items, such as highlightable sections,associated with a feature awarded in the game 16

[0021] A coin tray 30 is mounted beneath the console 12 for cash payoutsfrom the machine 10.

[0022] Referring now to FIG. 2 of the drawings, a control means orcontrol circuit 32 is illustrated. A program which implements the gameand user interface is run on a processor 34 of the control circuit 32.The processor 34 forms part of a controller 36 which drives the screenof the video display unit 14 and which receives input signals fromsensors 38. The sensors 38 include sensors associated with the bank 22of buttons and touch sensors mounted in the screen of the video displayunit 14. The controller 36 also receives input pulses from the mechanism24 to determine whether or not a player has provided sufficient creditto commence playing. The mechanism 24 may, instead of the coin inputchute 24.1 or the bill collector 24.2, or in addition thereto, be acredit card reader (not shown) or any other type of validation device.

[0023] Finally, the controller 36 drives a payout mechanism 40 which,for example, may be a coin hopper for feeding coins to the coin tray 30to make a pay out to a player when the player wishes to redeem his orher credit.

[0024] The game 16, in accordance with the invention, uses fixedpathways of outcomes during a feature event. Examples of pathways, whichare intended particularly for the second embodiment of the invention tobe described below but which also could be used in the first embodiment,are shown in FIG. 4 of the drawings and are designated generally by thereference numeral 50.

[0025] It will be appreciated that, in the case of a spinning reel gamehaving a number of lines which can be bought and where multiple creditscan be bet per line, various bets can be made by a player. The morelines bought and number of credits bet per line, the higher the wagermade by the player.

[0026] A set of pathways 50 is associated with each bet. Any number ofpathways constitutes each set. The reason for having a number ofpathways 50 associated with each bet is to increase the unpredictabilityof the outcome. Typically, fifty pathways 50 may be associated with eachbet. Each pathway 50 is constituted by a number of steps.

[0027] In the first embodiment of the invention, the flowchart of whichis shown in FIG. 3 of the drawings, each pathway 50 has a length offifty steps. For the embodiment of the invention shown in FIG. 5 of thedrawings, each pathway has a length exceeding one hundred steps.

[0028] Thus, it will be appreciated that the four pathways shown in FIG.4 of the drawings show only a part of the total length of each of thosefour pathways and are but a small sample of the total number of pathwaysassociated with the game 16. Thus, each pathway 50 shown in FIG. 4 ofthe drawings only has the first twenty-five steps shown, not the fullnumber of steps of each pathway 50.

[0029] The pathways 50 are used in a feature following a base game. Thebase game can be any suitable base game and need not be limited to aspinning reel game. However, for ease of reference the invention isdescribed with reference to the base game being a spinning reel gamehaving five reels 18.

[0030] In the embodiment of the invention of FIG. 3 of the drawings,once a trigger condition has occurred in the base game, for example, theoccurrence of three or more scatter symbols, a feature is triggered. Thefeature is a second screen feature. At the start of the feature apathway 50 is randomly selected from one of the sets of pathways.

[0031] In the second screen feature, once a “Start Feature” button hasbeen pressed in the bank 22 of buttons of the gaming machine 10, fivetreasure chests are displayed on the screen of the video display unit 14and the player is invited to choose a treasure chest from the fivedisplayed treasure chests. The player selects the treasure chest bytouching it. The chosen treasure chest animates to reveal a first prizedictated by the pathway previously selected by the controller 36 of thegaming machine 10.

[0032] A random selection is then made by the controller 36 to determinewhether or not to continue. If the answer is in the affirmative, theplayer is afforded a further chance to choose another treasure chestfrom a further set of five treasure chests. The treasure chest, onceagain, animates to reveal a prize at the second step or position alongthe pathway. This procedure continues until a decision has been made bythe controller 36 not to continue or the end of the pathway has beenreached.

[0033] Typically, for this embodiment of the invention a maximum limitto the number of steps down the pathway 50 which can be taken isenforced. Thus, as described above, each pathway 50 in the set has fiftysteps and if the fiftieth step is reached by the gaming machine, thefeature is regarded as completed and does not continue.

[0034] To serve as an encouragement to a player of this embodiment ofthe invention, there are a predetermined minimum number of steps at thebeginning of the pathway 50 that result in a positive outcome. In otherwords, once a pathway 50 has been selected there is a one hundred percent chance that at least three steps along the pathway will be taken.This is shown in detail in FIG. 3 of the drawings.

[0035] Referring now to FIG. 5 of the drawings, a second embodiment ofthe invention is described with reference to a modified version of theapplicant's Queen of the Nile TM game.

[0036] For every different total amount bet in the Queen of the Nilegame, a set of pathways 50 (once again, for example, fifty differentpathways) is provided. The theoretical return to player percentage foreach individual pathway 50 differs but, since the pathways 50 arerandomly selected from the set when the feature is triggered, theoverall expected return to player will be the average across all of thepathways 50 in the set associated with that particular bet. The set fromwhich the pathway 50 is selected is governed by, and associated with,the size of the bet made by the player. The pathways are establishedsuch that, in the pathways associated with larger bets, there is agreater probability of winning larger prizes than in pathways associatedwith smaller bets.

[0037] The return to player percentage of the game is calculated asfollows. Probabilities are calculated for each possible number ofspecial symbols (being a Cleopatra symbol) appearing anywhere over theentire free games feature. Since the free games can also bere-triggered, the probabilities of getting from zero to one hundredspecial symbols are separately calculated then the probability ofgetting more than one hundred special symbols is also calculated.

[0038] For each bet, a set of fifty predetermined pathways 50 isdeveloped which provide the separate outcomes for each special symbolduring the free game feature up to a possible one hundred steps alongthe pathway 50. A fixed prize of a low number of credits, for example,five credits, is used once more than one hundred special symbols haveappeared. As indicated above, the reason fifty pathways 50 are developedrather than just one is to avoid predictability of prizes forconsecutive special symbols.

[0039] The prize outcome at any one position along the pathway 50 isdependent on the probability of getting the required number of specialsymbols necessary to reach that position on the pathway 50. In otherwords, the value of each of the prizes is weighted to the number ofspecial symbol outcomes required in order to get those prizes.

[0040] In the Queen of the Nile game, there are four possible jackpotsbeing a grand jackpot, a major jackpot, a minor jackpot and a minijackpot. The probability of each jackpot being won is averaged over thefifty different pathways 50. These average probabilities are weighted tothe bet made. Thus, for a bet of five hundred credits, the probabilityof achieving the jackpot is approximately twenty times greater than fora bet of twenty-five credits. The bonus prizes are also averaged overthe fifty different pathways and weighted according to the bet. Thus,once again, the bonus prizes for five hundred credits are approximatelytwenty times greater than those for a bet of twenty-five credits. Thebonus prizes that are revealed along the pathway when jackpot symbolsare not revealed will be such that the average return to playercontributed by the prizes across the set of pathways applicable to thebet is the same for every possible total bet. Because the position ofthe jackpot symbols in the pathways will be different for different betsto compensate for the change in probability of winning a jackpot, thebonus prizes have to be independently calculated for every pathway ofevery total bet.

[0041] In FIG. 4 of the drawings it is shown that the chances of winninga jackpot prize are generally larger for the higher bet. If path A ofthe twenty-five bet pathway 50 is chosen then the player would need tohave twenty-four special symbols occurring in the free game seriesbefore that player would win a progressive mini jackpot. If path B ofthe twenty-five bet pathway 50 were selected by the controller, onlysixteen special symbols would be needed to win a minor jackpot and,after twenty-three special symbols had been spun up the mini jackpotwould also be won.

[0042] In contrast, if the maximum number of bets has been made by theplayer, being five hundred credits, then, if path A of the five hundredcredit pathway 50 were chosen by the controller 36, the player would winthe mini jackpot after the fourth special symbol had been spun up. Inthe case of path B of the five hundred bet pathway 50, the mini jackpotwould be awarded after five special symbols had been spun up, the minorjackpot after ten special symbols had been spun up and the major jackpotwould be awarded after twenty-two special symbols had been spun upduring the free game series.

[0043] While the invention has been described with reference to itsapplication in a stand-alone gaming; machine 10 it will be appreciatedthat it is equally applicable to gaming machines 10 of a linked system(not shown) where the gaming machines are linked via a network to ajackpot controller. Those skilled in the art will appreciate that, usingsuch linked systems, a percentage of the turnover of each gaming machinelinked to the network contributes to the jackpot pool from which thejackpot prizes, being the mini jackpot prize, the minor jackpot prize,the major jackpot prize and the grand jackpot prize, are paid.

[0044] It is a particular advantage of the invention that, even in theunlikely scenario that a player could memorise all the pathways 50 andrecognise what path they were on during a free game; feature, therewould still be anticipation in knowing what prizes were coming andattempting to chase the special symbols that are required in order towin them. In addition, it is also an advantage of the invention that itprovides a way to use pathways without having to fix the feature outcomeaccording to the path selected. This is achieved by having fixedpathways of outcomes which are used during a feature event but thenumber of steps which are taken down that pathway in any game variesrandomly for each feature event. Thus, even though the pathways arefixed, once the feature event has been triggered the outcome of thatfeature event is still not predictable as it remains unknown how manysteps down the pathway will be taken as the feature proceeds.

[0045] It will be appreciated by persons skilled in the art thatnumerous variations and/or modifications may be made to the invention asshown in the specific embodiments without departing from the spirit orscope of the invention as broadly described. The present embodimentsare, therefore, to be considered in all respects as illustrative and notrestrictive.

I claim:
 1. A gaming machine having a display means and a game controlmeans arranged to control images of symbols displayed on the displaymeans, the game control means being arranged to play a game in which atleast one random event is caused to be displayed on the display meansand, if a predefined winning event occurs, the machine awards a prize,wherein, when a game played results in a feature being awarded, toarrive at a determination of a result of the feature, the control meansselects a pathway having a number of steps, each step relating to aspecial outcome, with the number of steps taken along the pathwayvarying randomly from one feature to the next.
 2. The gaming machine ofclaim 1 in which the feature is a series of free games and the resultsof those free games are random and include the special outcomes.
 3. Thegaming machine of claim 1 in which the feature comprises a number ofspecial outcome selections available to the player.
 4. The gamingmachine of claim 3 in which the player is prompted to make a selectionfrom one of the special outcome selections whereafter, if the selection,as determined from the selected pathway, results in a positive outcome,the player is offered another opportunity to select a further specialoutcome until one of a fixed number of steps have been taken along thepathway and a negative outcome results.
 5. The gaming machine of claim 1in which a set of pathways is associated with each bet.
 6. The gamingmachine of claim 5 in which the pathways are weighted so that thoseassociated with larger bets provide an improved probability of obtaininglarger prizes than the pathways associated with smaller bets.
 7. Thegaming machine of claim 1 in which each pathway has a maximum number ofsteps that can be taken down the pathway, following which the feature isregarded as concluded.
 8. The gaming machine of claim 1 in which thepathways are of indefinite lengths where, if more than a predeterminednumber of steps down the pathway have been taken, thereafter each stepalong the pathway will provide a fixed, low credit prize.
 9. The gamingmachine of claim 1 in which there are a minimum number of steps to betaken down a pathway which result in positive outcomes in order toprovide encouragement to the player.
 10. The gaming machine of claim 1in which certain of the special outcomes are collected towards a furtherevent.